recently reported that travellers
who discover ticks attached to them should remove the tick by grasping the
mouthpiece with tweezers (forceps) and rotating the tick whilst withdrawing
it . Subsequently, readers and a posting to ProMED-mail
pointed out that other guidelines, including those of the World Health Organization
 and the United States’ Centers for Disease Control and Prevention 
do not advise rotating the tick during removal. Yet these guidelines also
differ from one another with respect to whether it is advisable to suffocate
ticks with paraffin or equivalent. Reasons behind the differing advice and
some basic common points shared by all guidance are discussed below.
Anatomy and physiology of feeding ticks
Ticks are arthropod vectors of a number of pathogens that cause potentially
serious human diseases such as Lyme borreliosis, Rocky Mountain spotted
fever, tickborne encephalitis, tularaemia and Q fever. A single tick can
carry a number of different pathogens , leading to atypical presentation
of tickborne illness.
Two classes of tick are responsible for disease in humans, hard ticks (family
Ixodidae) and soft ticks (family Argasidae), the principle
difference being the hard plate or scutum that hard ticks possess. There
is a third class of tick, family Nutalliellidae, of which only
one species is known, which is not of medical importance , Because soft
ticks take smaller, quicker blood meals at shorter intervals, they can transmit
pathogens much more quickly (within a minute of biting) than hard ticks
(hours or days) . However, hard ticks are more common, harder to remove
and more likely to transmit disease.
Ticks have a barbed, harpoon-like mouthpiece called a hypostome which they
insert into their host to suck blood. Many hard ticks also secrete a cement
which further strengthens their attachment. When removing ticks, it is important
not to squash the body (which could inject toxins or microbes into the host),
break off the mouthpiece or leave cement behind (which could lead to allergic
irritation from tick proteins or secondary bacterial infection).
Experimental evidence for tick removal techniques
There is very limited experimental evidence to support most suggested tick
removal strategies, and only a few reviews [7,8]. While both mechanical
removal and chemical incapacitation have their advocates, experimental evidence
suggests that chemical irritants are ineffective at persuading ticks to
detach, and risk triggering injection of salivary fluids and possible transmission
of disease-causing microbes. In addition, suffocating ticks by smothering
them with petroleum jelly is an ineffective method of killing them because
they have such a low respiratory rate (only requiring 3-15 breaths per hour)
that by the time they die, there may have been sufficient time for pathogens
to be transmitted.
One study compared several different techniques for removing ticks .
Application of petroleum jelly, fingernail polish, 70% isopropyl alcohol,
or a hot kitchen match failed to induce detachment of adult American dog
ticks (Dermacentor variabilis). Using forceps or grasping with
fingers as close to the skin as possible did remove the ticks. Rotating
the tick during removal did not appear more likely to damage the mouthparts
than pulling straight out, though twisting the tick was ultimately not recommended,
because of the risk of breaking of the mouthparts.
Three commercially available devices were compared to conventional forceps
for their effectiveness in removing lone star (Amblyomma americanum
(L.)) or American dog ticks (D. variabilis) from
laboratory rabbits . It was found that for adult ticks, forceps and
a commercial product that grasped the tick were superior to products with
a central V-shaped groove that were designed to scoop the tick off. Conversely,
removal of nymphs (immature ticks) with forceps tended to leave the mouthparts
behind more often than removal with the grooved devices. A variety of other
techniques were tested, including fingernail polish, petroleum jelly, a
glowing hot match, 70% isopropanol and injection of local anaesthetics (lidocaine,
lidocaine with epinephrine, and chloroprocaine). None of these methods initiated
A Spanish study that compared the outcomes of people who removed ticks
using forceps and those who used other methods found that people who used
forceps were significantly less likely to experience complications, including
the skin disease erythema migrans* and secondary
bacterial infections .
A Dutch study compared the ease of removal and retention of mouthparts
using several techniques: applying gasoline, 70% isopropyl alcohol or a
hot match, pulling clockwise or pulling straight out with quick or steady
even pressure using conventional forceps or ’Tick Solution’ forceps .
Chemical methods failed to cause ticks to detach within half an hour, and
pulling the ticks straight out was significantly less likely to lead to
retained mouthparts than rotational pulling. An American study compared
conventional forceps against ’Tick Solution’ forceps and found the conventional
forceps to be superior .
Nevertheless, at least one company specifically markets a veterinary product
that catches the tick in a groove in a plastic device that is then rotated
several times. It claims that the rostrum spikes fold into the axis of rotation,
facilitating tick removal without the risk of snapping off the hypostome,
and provides video evidence of this technique working on the company’s website
Other mechanical techniques have been described, with anecdotal levels
of evidence. Lassoing the tick as close to the skin as possible, using a
loose knot of cotton thread, such as from clothing, then applying gentle
traction, can remove ticks when forceps are not available . Disposable
razors have also been suggested .
Relatively few studies have been conducted in this area, and those that
have been vary with respect to different tick species, different host species
and different time periods of tick attachment before removal. When the species
of tick is known to be of the soft family, and disease in humans is not
endemic in an area, the World Health Organization recommendation of chemical
methods of removing ticks may be appropriate . However, since many people,
particularly travellers who are not familiar with an area, will not be able
to distinguish between different types of tick or know the local prevalence
of disease, it seems sensible to recommend always removing ticks by grasping
with forceps as close to the skin as possible and pulling straight out to
avoid leaving mouthparts behind. There is a clear and simple image that
illustrates this at reference 4.
*Correction. This was corrected
from 'larva migrans' to 'erythema migrans' at the author's request on 18
Eurosurveillance editorial office, 18 August 2006.